Piston



Nov. 27, 1934.. b. SULPRIZIO PISTON Filed Feb. 12, 1932 INVENTOR. DEUTA JULPfi/l/O ATTORNEYS.

Patented Nov. 27, I934 UNITED STATES PATENT-O JK I PIsToN I Deuta. Sulprizio, San Leandro,- Calif. Application February 12, 1932, Serial No. 592,596

i 6 Claims. (01. 309-11 This invention relates to split skirt pistons and free to expand, but 14 is the only one which is has for its objects improved construction of such bottomed and for a reason which will be later pistons whereby a better distribution of heat explained. This ring 14, as stated, gathersand and of the working stresses set up is obtained, drags the oil under it and-discharges it through .l a more perfect fit is maintained in the cylinder the holes 15. i

under temperature and wear changes, andeffec- Hubs7 are entirely free from skirt 2 and holes tive' lubrication without oil pumping is assured. 7 a e med th at l r a e u s Other objects and advantages of the invention so as to ve e e p v a d n act e V will appear in the following description and acment tOVthe Skirt, a e dreinegee of from -1I companyingdrawing. force feed on the pin bearings into theinside of Inthe drawing Fig. 1 is a vertical section of the piston my improved piston positioned within the walls The lower margin of 001110811 m 3 s cut of a cylinder but with'the wrist pin and con- W y a foul points as at 50 as meeting rod omitted, the-section being taken o p ovide four legs *or points of juncture of HI through the hubs of the wrist pin bosses. member 3 w the "flange rib 6 0f the S the 70 Fig. 2 is a similar view to that of Fig. 1 but four legs thus formed a spa d inward y from is taken on a line at right angles to the section the Skirt 50 as to ave a a ular Channel of Fig, 1. I i between the legs and the skirt and the bottom In further detail, the cylinder is indicated at x, of s p d to a h po t 21 behind each '20 and the piston comprises a head portion 1, a leg e a Oil W l r lheut. 7 skirt portion 2, and an internal boss-carrying The side Well of the skirt p s t th p ssu e portion 3 connected at its upper end at 4to the Side (caused by angle of erehk p the pow head portion and at its lower end at 5 to the Stroke)" iS Vertieellyv Slotted as 22 through skirt portion, or rather to an internal circumthe upper end w to a Po t ear the bottom ferentially extending rib 6; This internal por- 0f the hubs and terminating in a hole and 0 tion 3 is conical in form and s rt th pin on thetwo sides at right angles to this slot the osses 7 which are cast integrally to it, and f lower end of the skirt is vertically slotted as at ther braced bya short triangular-shaped vertical 24 to join the hub Clearance Opening 7, thus rib8 extending just to the underside of the piston ferming very resilient Disten Skirt Wel Without head, the objection of slotting the skirt clear through. 3

The head 1 is a thick diskrormed'with adownh great l h f co calm mber 3 and its wardly extending peripheral flange 9, the outer attachment at the extreme lower end to the surface of which is circumferehtially grooved'at ,lOWer end of the Skirt, overcomes the j c i 10 for th piston rings 11 d it is entirely arable rigidity in earlier constructions of this type.

rated from the skirt or sleeve portion2 by an At 'p the pressure Side Of the piston 90 annular slot 12 which extends clear around the substantially oppesitehele 3 i a s a l p st or piston and within which slot is a piston ring 13. p d 25 integrally Connecting the pp thick- The upper end of the skirt or leev portion ened margin of the skirt'with the conical hub of the piston is made about three times as thick ar i r 3 f r the p p s f'su tai in the struc- 40 as the skirt and formed with a piston ring groove tule at his point of gr a pressure e e 5 in which is bottomed a ring 14, while small holes pi n i us d an x iv n e.

15 drilled through this groove to the space be- It should be noted that the upper end of the tween the skirt and the hub supporting member 3 conical hub carrier joins the piston head 1 at a are provided so as to discharge excess oil to said point spaced well wa d y m e p t an space. 9 and this results in the included head area 5 Rings 13 and 14 are slightly narrower in thickwithin the conical wall 3 being substantially ness than the width of the slot and groove reequal to the head area between wall 3 and flange speotively in which they operate so that excess 9 with aresult that the head is evenly Supp oil scraped up on the downward stroke by their against the shock of exploding gases in two cirlower corners can readily escape below the ring cular areas. to the hollow space within the piston, and to The conical form of the hub carrier 3 and facilitate this oil scraping action the corners close juncture with the skirt at its lower edge of the slot and groove are chamfered off as at 16 in four spaced places makes for unusual flexibilat the under sides of the rings. All the rings ity at this point where heretofore a resistance '55are supposed to be common split piston rings to compression or flexibility was set up. The In conical shape of the hub carrier extending downward from an intermediate point on the piston head also transmits the explosive blow evenly therefrom to the hubs and pin. 5 The piston is designed especially for aluminum alloy castings carried out with sand cores, and any required holes for supporting the core of the intershell space may be left through the wall of member 3 above the hubs. In making these pistons the upper portion 9 is made slightly smaller in diameter than the skirt so that the split rings 10 will effect the seal in the usual way. Ring 13 also being a split ring contributes considerably to the sealing action while also functioning as a special oil scraper as well as a barrier against uninterrupted transmission of heat from the head to the skirt as there are always changing oil films to crossi a In pistons of this kind it is the practice to have the head portion which carries rings 10 of a trifle smaller diameter than the bore of the cylinder and let the rings effect the seal. The skirt portion, however, is for the purpose ofguiding the piston and should fit smoothly within the bore, but on account of the great expansive effect of aluminum alloys when heated, the diameter of the skirt is made a trifle small so that when fully heated it will not be too tight. This usually means that the skirt is just a trifle free in the cylinder when cold, and hence is liable to rattle until heated. My provision of split ring 14. in the upper end of the skirt overcomes this entirely, for it is of iron or steel and of an external diameter to just fit nicely within the cylinder when bottomed in its groove so that when startingcold the skirt willnot rattle and when heated up the aluminum alloy skirt portion being of greater co-eflicient of expansion will enlarge to just equal the ring diameter so that the whole skirt will take the wear. Thus the cold piston skirt first finds bearing through ring 14 and as soon as hot also findsbearing throughout its length, and this effectually prevents rattling or slapping. Besides this, the ring will scrape off and guide most of the oil back into the hollow piston, so that any surplus passing this ring will be picked up by. ring 12 for guid-.

ing through slot 12 by ring 13.

Having thus described my improved piston,

whatIclaimis:-,-

1. A piston comprising an inverted cup-shaped head, a skirt separated from said head, an inside structure connecting the under-side of said head circumferentially with the margin at the lower end of said skirt, wrist pin bearing bosses on said inside structure free of said skirt, and means connecting said structure and the. upper end of said skirt in a limited region intermediate said bosses at one side of theskirt only.

structure free of said skirt, and means connect- 2. A piston comprising an inverted cup-shaped head, a skirt separated from said head, an inside structure connecting the under-side of said head circumferentially with the margin at the lower end of said skirt, wrist pin bearing bosses on said inside structure free of said skirt, and means integrally connecting said structure and the upper end of said skirt in a limited region intermediate said bosses at one side of the skirt only.

3. A piston comprising a head, a skirt separated from said head, an inside structure connecting said head with the lower end of said skirt, wrist pin bearing bosses on said inside ing said structure and the upper end of said skirt in a region intermediate said bosses, said skirt beingsplit in the region between the wrist pin bearing bosses opposite said means.

4. A piston comprising a head, a skirt separated from said head, an inside structure connecting said head with the lower end of said skirt, wrist pin bearing bosses on said inside structure free of said skirt, and means connecting said structure and the upper end of said skirt in a region intermediate said bosses, said skirt being split in-theregion between the wrist pin bearing bosses opposite said means to the upper end of said skirt.

5. In a piston provided with a head and a skirt separated from the head, an internal structure depending from the head supporting wrist pin bosses free from the skirt and suspending the skirt by connections thereto around its lower end below the bosses and forming a channel between the skirt and the internal structure, the upper surface of said channel formed with a slant to discharge oil from between the skirt and internal structure.

6. An aluminum alloy hollow piston comprising a head portion, and a split skirt portion separated from the head portion by a circumferential slot, means within the hollow piston integrally connecting the lower margin of the skirt portion with the under side of the head portion, split piston rings in the head portion, and an iron split piston ring carried wholly by and bottomed throughout its circumference in a groove in the upper portion of the split skirt portion, said iron ring being of an external diameter to bear against the cylinder walls when the skirt is cold for guiding the skirt, and the diameter of the skirt when cold being of slightly less diameter than the diameter of said ring, and

substantially equal thereto when hot. 13

DEUTA SULPRIZIO. 

